From Halopedia, the Halo wiki
Zelfiss was a region on Janjur Qom, the San'Shyuum homeworld. Bordering the Great Apothtea, Zelfiss was the location of the fabled Reformist fortress of Granduin. During the San'Shyuum Schism, the Stoics undermined the fortress and it crumbled into the Apothtea sea.
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